Complexes of Nitrilotriacetic Acid with Amines. Molecular Structures of 2-Ammonioethanol Nitrilotriacetate and Bis{2-Ammonio-2-(Hydroxymethyl)propane-1,3-Diol} Nitrilotriacetate

Crystallography Reports - Reactions of nitrilotriacetic acid with 2-aminoethanol, 2-amino-2-(hydroxymethyl)propane-1,3-diol, and 2,2'-(ethylenedioxy)bis(ethylamine) afford the following salts...     

Experimental study of X-ray charge density and the selection of reference points for a source function in η6-(2-methyl-1,4-dihydro-2H-3,1-benzoxazine)tricarbonylchromium(0)

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Crystallization of Complexes of Nitrilotriacetic Acid with Organic Amines. Molecular Structure of Hexamethylene-1,6-Diammonium Nitrilotriacetate

Crystallography Reports - Methods are described for the synthesis and purification by recrystallization of amine nitrilotriacetate salts N(CH2COOH)3: bis(propionic acid 2-ammonium)...     

Comparison of Experimental and Experimental–Theoretical Topological Characteristics of the Electron Density in the Crystalline Complex η6-[3-Acetyltetrahydro-6-Phenyl-2Н-1,3-oxazine]tricarbonylchromium(0)

Russian Journal of Coordination Chemistry - Experimental and experimental–theoretical studies (using the molecular invariom) of the electron density distribution are performed for the...     

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis,Structure, Redox and Catalytic Properties

A new monoiminoacenaphthenone 3,5-(CF₃)₂C₆H₃-mian (complex 2) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl₂(dpp-mian)(CH₃CN)] (3) and [VOCl(3,5-(CF₃)₂C₆H₃-bian)(H₂O)][VOCl₃(3,5-(CF₃)₂C₆H₃-bian)]·2.85DME (4) from [VOCl₂(CH₃CN)₂(H₂O)] (1) or [VCl₃(THF)₃]. The structure of all compounds was determined using X-ray structural analysis. The vanadium atom in these structures has an octahedral coordination environment. Complex 4 has an unexpected structure. Firstly, it contains 3,5-(CF₃)₂C₆H₃-bian instead of 3,5-(CF₃)₂C₆H₃-mian. Secondly, it has a binuclear structure, in contrast to 3, in which two oxovanadium parts are linked to each other through V=O···V interaction. This interaction is non-covalent in origin, according to DFT calculations. In structures 2 and 3, non-covalent π-π staking interactions between acenaphthene moieties of the neighboring molecules (distances are 3.36–3.40 Å) with an estimated energy of 3 kcal/mol were also found. The redox properties of the obtained compounds were studied using cyclic voltammetry in solution. In all cases, the reduction processes initiated by the redox-active nature of the mian or bian ligand were identified. The paramagnetic nature of complexes 3 and 4 has been proven by EPR spectroscopy. Complexes 3 and 4 exhibited high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The yields of products of cyclohexane oxidation were 43% (complex 3) and 27% (complex 4). Based on the data regarding the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play the most crucial role in the reaction. The initial products in the reactions with alkanes are alkyl hydroperoxides, which are easily reduced to their corresponding alcohols by the action of triphenylphosphine (PPh₃). According to the DFT calculations, the difference in the catalytic activity of 3 and 4 is most likely associated with a different mechanism for the generation of ^●OH radicals. For complex 4 with electron-withdrawing CF₃ substituents at the diimine ligand, an alternative mechanism, different from Fenton’s and involving a redox-active ligand, is assumed.     

Utilizing o-quinone methide chemistry: synthesis of sterically hindered acridin-4-ols

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One-Electron Reduction of 2-Mono(2,6-diisopropylphenylimino)acenaphthene-1-one (dpp-mian)

The electrochemical characteristics of 2-mono(2,6-diisopropylphenylimino)acenaphthene-1-one (dpp-mian) have been investigated. One-electron reduction of dpp-mian involves the iminoketone fragment, which is revealed by the EPR spectrum obtained after the electrolysis of the dpp-mian solution in tetrahydrofuran (THF). The reduction of dpp-mian with one equivalent of metallic potassium leads to a similar EPR spectrum. The sodium complex [(dpp-mian)Na(dme)]₂ ( 1 ) produces an EPR signal with hyperfine coupling on the nitrogen atom of the iminoketone fragment of the dpp-mian ligand. Dpp-mian can also be reduced in a one-electron process by SnCl₂×(dioxane). In this case, complex (dpp-mian)₂SnCl₂ ( 2 ) is formed, with the tin atom displaying an oxidation state of +4. Tin(II) chloride dihydrate, SnCl₂×2(H₂O), also reduces dpp-mian, but the two ligands bound to tin in the product form a new carbon–carbon bond between the ketone moieties of the dpp-mian monoanions to form complex (bis-dpp-mian)HSnCl₃ ( 3 ). Metallic tin reduces dpp-mian to form the (bis-dpp-mian)₂Sn ( 4 ) species. Compounds 1 – 4 were characterized by X-ray diffraction.     

Synthesis,structure, and luminescence properties of sodium and ytterbium complexes with 2-(benzothiazol-2-yl)selenophenolate ligands

Russian Chemical Bulletin - With the aim of designing new heteroorganic ligands capable of sensitizing the metal-centered photoluminescence (PL) of YbIII through the redox mechanism, a new...     

Synthesis and Luminescent Properties of Lanthanide Complexes with Benzothiazolylphenolate and -Naphtholate Ligands

Russian Journal of Coordination Chemistry - Sm, Er, and Yb complexes containing anionic (4,5,6,7-tetrafluorobenzothiazol-2-yl)-2-(3,4,5,6-tetrafluoro)phenolate (SONF) and...